Apparatus for printing by means of an electron beam



Nov. 17, 1964 J. D. KUEHLER APPARATUS FOR PRINTING BY MEANS OF ANELECTRON BEAM Filed D60. 28, 1959 3 Sheets-Sheet 1 INFORMATION STORAGESWITCHING MECHANISM SYNCHRONIZING CIRCUITS SWEEP VOLTAGE INVENTOR.

JACK D. KUEHLER Nov. 17, 1964 3 Sheets-Sheet 2 N R JACK 0. KUEHLER Nov.17, 1964 J. D. KUEHLER 3,157,879

APPARATUS FOR PRINTING BY MEANS OF AN ELECTRON BEAM Filed Dec. 28, 19595 Sheets-Sheet 3 obcde obcde ubcd FIG. 40

FIG. 4b

FIG. 40

O0 OO O OO'O FIG. 4d

FIG. 4e

INVENTOR.

39 34 55 55 JACK D. KUEH United States Patent 3,157,879 APPARATUS FORPRINTING BY MEANS 8F AN ELEUIRUN BEAM Jack D. Kuehier, San Jose, Caiitl,assignor to Internet tional Business Machines Corporation, New Yorir,N.Y., a corporation of New York Filed Dec. 23, 195%, Ser. No. 862,324 6Claims. (Cl. ass-74 The present invention relates to apparatus forprinting letters, numerals and like symbols by means of an electron beamupon heat sensitive surfaces.

It is an object of my invention to provide a rapidly operating apparatusfor printing information by means of an electron beam upon sensitizedrecording surfaces.

More particularly, it is an object of the invention to provide a cathoderay tube for printing information by means of an electron beam uponsurfaces located eX- teriorly of the tube.

Still another object of the invention is to provide a device of the typereferred to that may rapidly be set to print any desired symbol or anydesired sequence of dif ferent symbols.

An additional object of the invention is to provide an apparatus of thetype referred to, with means that may readily and rapidly be adjusted tocause the electron beam to print a selected symbol and/or a sequence ofdifierent selected symbols upon an exteriorly located recording surface.

In this connection it is another particular object of the invention toprovide an adjustable stencil for printing by means of an electron beam,which is of simple construction and may rapidly be adjusted to differentsymbols.

A further object of the invention is to provide an electricallycontrolled adjustable stencil of the type referred to that requires aminimum of control leads to set up any desired sequence of symbols suchas are necessary to print a desired sequence of words.

These and other objects of the present invention will be apparent fromthe following description of the accompanying drawings which illustratea preferred embodiment thereof and wherein FIGURE 1 is a fragmentaryperspective of an electron beam printing apparatus embodying myinvention;

FIGURE 2 is a vertical cross section taken along line 2-2 of FIGURE 1and viewed in the direction of the arrows associated with said line;

FIGURE 3 is an enlarged fragmentary plan view of the device forpredetermining the symbols to be printed by the electron beam; and

FIGURES 4a, 4b, 4c, 4d and 4c are plan views of components of the deviceshown in FIGURE 3 illustrating its electrical connections, and themanner in which the device may be assembled in the manufacture thereof.

Having first reference to FIGURE 1, the apparatus of the invention isbasically a cathode ray tube and comprises an evacuated envelope 12which has a narrow neck 14, and opposite said neck a fiat bottom 16.Located in the neck 14 is the electron discharge cathode 18, which maybe surrounded by a control electrode 20 to predetermine the intensity ofthe electron stream emitted by the cathode. Arranged in the front of thecathode is an apertured anode 22 which is held at a high positivepotential relative to the cathode as indicated by the battery 24, todirect the stream of electrons emitted by the cathode in a beam towardthe flat bottom of the envelope.

Provided in the fiat bottom In of the envelope is a linear elongatedslot 26 that extends diagonally across said bottom but terminates ateither end a limited distant/e removed from the peripheral edge thereof.Said slot is of a transverse width about equal to the height of aprinted line, and flush with the outer surface of the flat bottom 16 ofenvelope I2 the slot is closed in an air-tight manner by a thin sheet orplate 28 (FIGURE 2) to maintain the interior of the envelope inevacuated condition. Said sheet 28 is made of a conductive material,such as aluminum or beryllium, and is extremely thin, for instance.00025 inch, to form an electron window through which the electronsemitted by the cathode 18 and accelerated toward the bottom of theenvelope by the anode 22 may readily pass.

Means are provided in the form of a pair of deflection plates 39a and30b and suitable control circuitry for said plates, indicated by theblock 32, to sweep the beam of electrons emitted by the cathode 13continually over and along the slot 26. Located in said slot above theelectron window 28 is a strip 34 of a dielectric material, such as glassor mica, which forms a row of symbol-forming units 36 of identical sizeand construction. Said units are comparable tostencils used in the artof brush painting or spraying and may be set to permit passage ofelectrons from the interior of the envelope through the window 28 ontoan exteriorly located sheet 38 of heat sensitive paper in such locationsonly as will form a selected symbol thereon.

Having particular reference to FIGURES 2 and 3, each of saidsymbol-forming units is formed by a section of the strip 34 as indicatedby the vertical phantom lines 35 in FIGURES 3 and 4a to 4e, and eachsuch section of the strip 34 is provided with an array of holes orpassages 39 extending from the top to the bottom surface thereof (FIGURE2). In the embodiment of the invention illus trated in the accompanyingdrawings each such section 36 contains five juxtaposed rows a, b, c, dand e of seven holes each, as best illustrated in FIGURE 3, so that eachsymbol-forming unit is actually provided with thirty-five holes 39. Bypermitting selected ones of said thirty-five holes to pass electronsemitted from the cathode 18 while blocking the remaining holes, anyletter of the alphabet or any character from 0 to 9 may be formed asillustrated in FIGURE 3 wherein holes blocked to the passage ofelectrons are identified by shade lines. In the first symbol-formingunit illustrated in FIGURE 3 the holes left open to the passage ofelectrons form the character 2; in the second symbol-forming unit theyform the letter E.

To be able to selectively control the passage of electrons through theholes 39 I furnish each hole with an electrically conductive lining suchas a thin metal tube 49 and I provide means for applying individually toevery one of the tubes 40 (FIGURE 3) in each unit a potential thatblocks the hole effectively against passage by the electrons emittedfrom the cathode 18 or slows them down sufiiciently so that they willnot penetrate the electron window. Thus, as the electron beam emitted bythe cathode 18 is swept over and along the inner surface of the row 34of symbol-forming units 36, the presence or absence of appropriateelectrical potentials upon selected tubes 40 of each symbol-forming unitdetermines where the electrons may pass through said units and theelectron window 28 to impinge upon the heat sensitive sheet 328 and formselected symbols thereon, and the heat sensitive sheet may be moved pastthe window 28 in synchronism with the sweeping speed of the electronbeam. This may be accomplished by an electric motor such as indicated atat in FIGURE 1.

To control every one of the holes in the row of symbolforming unitsindividually would ordinarily require as many individual leads as thereare holes in all the symbolforming units comprised in the stencil strip34, and since a line of printed information may require as many as onehunder letters and/or letter-sized spaces, it would require as many asthirty-five hundred individual leads to control every one of thesymbol-forming units 31: in the row 34 individually. In accordance withmy invention, however,

aun /ere I provide an arrangement for the control of all thesymbol-forming units in row 34, that requires no more leads than thenumber of leads necessary to control the holes in a singlesymbol-forming unit. For this purpose I connect the identically locatedtubes of all the symbol-forming units comprised in the apparatus inparallel to common control leads 51 as illustrated in FIGURES 4a to 46,which show individual plan views of five vertically superposed strata ofstrip 34 and which will be described in greater detail hereinafter. Whenthe identically located tubes of all the symbol-forming units comprisedin row 34 are all connected in parallel to common control leads, thetotal number of control leads for all the symbol-forming units in saidrow 34, no matter how many there may be, will always be equal to thenumber of holes 3% provided in each symbol-forming unit, and blockingpotentials applied to selected ones of said control leads to set up aselected symbol in any one of said units will automatically andsimultaneously set every one of the symbol-forming units comprised inthe row to the same symbol. To enable the apparatus of the invention toprint information composed of different symbols as the electron beamsweeps over the row of symbol-forming units, it is necessary thereforethat the operation of the sweep circuitry 32 which controls the speedwith which the electron beam is swept over the row of symbol-formingunits be synchronized with the speed of operation of the switchingmechanism which applies blocking potentials to selected ones of thecommon control leads of the symbol-forming units to establish theselected symbols, so that the blocking potentials which are to form adirectly consecutive symbol be applied to the common control leads bythe time the electron beam sweeps over the next symbol-forming memher.

In FIGURE 1 the switching mechanism which applies blocking potentials tothe appropriate control leads is represented by the block 42, and themechanism which supervises both the sweep circuitry 32 and the switchingmechanism 42 so that they may operate in synchronism is indicated by theblock 44. The switching mechanism 42 in turn may be controlled from andactivated by an information storage device in which the information tobe printed is stored and which is represented by the block &6. Switchingarrangements, information storage devices, in-

formation recovery arrangements and synchronizing circuitry such asrepresented by the blocks d2, 44 and 46 are well known in the art ofrecording information and recovering recorded information, they do notby themselves constitute part of the present invention so that it isunnecessary to describe them in greater detail.

The best way to produce a strip of symbol-forming units with its manyholes and electrical connections is to assemble it from as manycomponent strips as there are juxtaposed rows of holes in each unit. Inthe embodiment of the invention illustrated in the accompanying bledfrom five component strips 34a, 34b, 34c, 34d and 34:2

which are illustrated in FIGURES 4a to 4e respectively. The holes in thestrips may be drilled or etched in any suitable manner into said stripsprior to assembly thereof.

In strip 34a the top holes in the leftmost row a of all the sections areall connected to a longitudinally extending control lead Sin and thesecond, third, fourth, fifth, sixth and seventh holes in the leftmostrow a of all the sections are all connected to common longitudinallyextending control leads 52a, 53a, 54a, 55a, 56a and 57a respectively.These control leads and the short branches leading from the holes to thecontrol leads may be produced by conventional printed circuit methods orby evaporation of metal through masks. In the second component strip3411 the top holes in the second row b (counted from the left) of allthe sections are all connected to a longitudinally extending controllead 511), and similarly the second, third, fourth, fifth, sixth andseventh holes in said second rows b of all the sections are allconnected to longitudinally extending control leads 52b, 53b, 54b, 55b,55b and 5%, respectively, as illustrated in FIGURE 4b. In the thirdcomponent strip 340 identically located holes in the third row of holes0 are connected to longitudinally extending control leads 51c, 52c, 53c,54c, 55c, 5dr: and 570, respectively, as illustrated in FIGURE 40, andin the fourth and fifth component strips identically located holes inthe fourth and fifth rows 0. and e, respectively, of all the sectionsare all connected to common longitudinally extending control leads 51d,52d, 53d, 54a, 55a, 56d and 57d and 51e, 522, 53c, 54e, 55a, 56a and57a, respectively, as illustrated in FIGURES 4d and 42. When thedescribed connections have been established, the five component strips34a, 34b, 34c, 34d and 34s are superposed and suitably secured to eachother in such a manner that the holes in the corresponding groups ofholes of the five strips are perfectly aligned vertically and formpassages 39 extending from the top to the bottom surface of theresulting composite strip 34 (FIGURE 2). A metal may now be evaporatedthrough these passages to provide conductive linings inside thesepassages corresponding to the hereinbefore described conductive tubes49.

In the composite strip thus produced the conductive linings 4b ofidentically located holes 39 in every one of the consecutivesymbol-forming units of the strip are connected to common longitudinalleads 51a to 57a, 51b to 57b, 510 to 57c, 51d to 57:! and 51e to 5%,that project from one end edge of the strip. These leads are connectedto the hereinbefore described switching mechanism represented by theblock 42 in FIGURE 1, that energizes appropriate ones of said leadsunder control of the information storage device 46 to establish in rapidsuccession selected characters in all the symbol-forming sections of thestrip as the electron beam sweep across the inner surface of said stripin synchronism with the speed with which the means for recoveringinformation from the storage device 46 establishes new settings of thevoltage distributing switching mechanism 42.

The printing apparatus of the invention may be capable of extremelyrapid operation. When a flood beam of a size appropriate to cover asingle unit 3d and of a current strength of .5 milliarnpere is sweptover the stencil strip, the strength of the electron current thatreaches the heat sensitive paper held against the window 28, through theindividual holes 39, is of the order of 7 microarnperes, which issufficient to produce a distinct mark upon heat sensitive paper, such asChalkley paper, in a time interval of the order of 10micrornicroseconds. At the same time, the blocking potentials applied toselected ones of the linings id of the stencil holes 39 may beestablished and abolished with utmost rapidity. As a result thereof, theapparatus of the invention is capable of printing one hundred lines eachof one hundred letters per second. As an added advantage the printingapparatus of the invention and particularly the adjustable electronstencils employed therein may be made very small so that the symbolsestablished by said stencils may equal typewritten characters in size.Furthermore, in spite of the fact that the stencil strip may be set toestablish a whole line of different symbols in a minimum of time, itsconstruction and especially its control connections are rather simple inthat the total strip with its many symbol-forming units requires no morecontrol leads than ordinarily required for a single symbol-forming unit.

While I have described my invention with the aid of an exemplaryembodiment thereof, the invention is not limited to the specificconstructional details shown and described by way of example which maybe departed from without departing from the scope and spirit of theinvention.

I claim:

1. A printing apparatus comprising an evacuated envelope, anelectron-emitting electrode provided widiin said envelope, anelectron-permeable window provided in said envelope opposite saidelectrode, a member of dielectric material having a plurality ofchannels adapted to pass electrons arranged over said window, means forblocking selected ones of said channels to the passage of electrons toestablish electron passing areas of desired conformation, and means forsweeping the electrons emitted by said electrode over said member.

2. A printing apparatus comprising an evacuated envelope, anelectron-emitting electrode provided within said envelope, anelectron-permeable window provided in said envelope opposite saidelectrode, a member of dielectric material having a plurality ofchannels adapted to pass electrons arranged over said window within saidenvelope, means for blocking selected ones of said channels to thepassage ofelectrons to establish electron passing areas of desiredconformation, means for conducting a sensitized sheet past said windowexterior-1y of said envelope, and means for sweeping the electronsemitted by said electrode over said window.

3. A printing apparatus comprising an evacuated envelope having a fiatbottom, an electron-emitting electrode provided within said envelopeopposite said flat bottom, an electron-permeable window provided in saidbottom, a strip of a dielectric material disposed over said Windowwithin said envelope, said strip having a plurality of channels adaptedto pass electrons, means operable to block selected ones of saidchannels to the passage of electrons so that those left unblocked mayform desired symbols, and means for sweeping the electrons emitted bysaid electrode over said strip,

4. A printing apparatus comprising an evacuated envelope having a fiatbottom, an electron-emitting electrode provided within said envelopeopposite said fiat bottom, an electron-permeable window provided in saidbottom, a strip of a dielectric material disposed over said windowwithin said envelope, said strip having a plurality of channelsextending normal to said window and adapted to pass electrons, meansoperable to place electrostatic charges to selected ones of saidchannels to block them effectively to the passage of electrons so thatthose left unblocked may form desired symbols, means for passing asensitized sheet along said window exteriorly of said 6 envelo e andmeans for sweeping the electrons emitted by said electrode over saidstrip.

5. A printing apparatus comprising an evacuated en velope, an electronbeam emitting electrode arranged within sad envelope, an elongatedwindow of electronpermeable material provided in said envelope in anarea opposite to said electrode, a strip of dielectric material placedover the inside of said window, said strip having a sequence of groupsof channels extending from the interior of said envelope to said windowto permit electrons emitted from said electrode to pass to and throughsaid window, means for applying electron flow blocking potentials toselected channels of said groups to block the passage of electronsthrough said selected channels so that the unblocked channels mayestablish desired symbols, and means for sweeping the electron beamemitted by said electrode across the inner surface of said strip.

6. A multi-symbol stencil for electron beam printing comprising aplurality of superposed strips of a dielectric material havingvertically aligned arrays of holes arranged in juxtapositionlongitudinally of said strips, each of said arrays being comprised oftransverse rows of holes equal to the number of superposed strips andeach of said strips carrying a number of longitudinally extending leadsequal to the number of holes comprised in each of the transverse rows ofsaid arrays, electrically conductive linings in the passages formed bythe vertically aligned holes of said superposed strips, and means onsaid strips connecting the linings of identically located holes inidentically located vertical rows of the array of holes provided in saidstrips to identical ones or" the longitudinal leads passing through saidstrips.

References Cited in the tile of this patent UNITED STATES PATENTS2,716,048 Young Aug. 23, 1955 2,771,336 MacGriff Nov. 20, 1956 2,793,178Morris May 21, 1957 2,862,144 McNaney Nov. 25, 1958 2,879,422 Borden etal Mar. 24, 1959 2,930,847 Metzger d. Mar. 29, 1960 2,978,608 GaffneyApr. 4, 1961 FOREIGN PATENTS 1,077,037 France Apr. 20, 1954

1. A PRINTING APPARATUS COMPRISING AN EVACUATED ENVELOPE, ANELECTRON-EMITTING ELECTRODE PROVIDED WITHIN SAID ENVELOPE, ANELECTRON-PERMEABLE WINDOW PROVIDED IN SAID ENVELOPE OPPOSITE SAIDELECTRODE, A MEMBER OF DIELECTRIC MATERIAL HAVING A PLURALITY OFCHANNELS ADAPTED TO PASS ELECTRONS ARRANGED OVER SAID WINDOW, MEANS FORBLOCKING SELECTED ONES OF SAID CHANNELS TO THE PASSAGE OF ELECTRONS TOESTABLISH ELECTRON PASSING AREAS OF DESIRED